A new front is emerging in the fight against antibiotic-resistant superbugs—one that doesn’t involve the development of new drugs.

Companies are racing to develop diagnostic technologies that can be used by hospitals and clinics to pinpoint the cause of common infections quickly. That should cut down on the unnecessary prescription of antibiotics, a major driver of drug-resistance in bacteria.

Traditional diagnostic testing via specialist laboratories can take several days to deliver results, so doctors who want to prescribe an immediate remedy often use a patient’s symptoms to guess what is causing an illness. More than a quarter of the time, this leads to antibiotics being prescribed unnecessarily, according to a 2013 study in the U.S. published in the Journal of Antimicrobial Chemotherapy. In respiratory infections, two thirds of antibiotic prescriptions are unnecessary, according to the same study.

Now, a new market is opening up for diagnostics that can be used outside of specialist labs, and it is growing at a steady clip. The U.S. market for so-called point-of-care diagnostics for infectious disease stands at $533 million and is growing 7% a year, according to Divyaa Ravishankar, an analyst at consultancy Frost & Sullivan.

There is pent-up demand for tests that can return results quickly, said Nicholas Jansen, an analyst at Raymond James. “There’s always been a desire by hospitals and government agencies to minimize the use of antibiotics,” he said. “But the problem was that there wasn’t a technology available…that would make it cost-effective.”

Carl Heneghan, professor of evidence-based medicine at the University of Oxford, said the tool that doctors want most is one that can test for several potential culprits simultaneously.

BioFire Diagnostics Inc., a Salt Lake City-based division of France’s
bioMérieux SA,
makes one such device. Its test looks for several pathogens at once, depending on the type of infection, and produces results in about an hour. Sales of these devices, which cost $35,000 apiece, more than doubled in the past year, according to company filings.

Belgium-based
Biocartis Group
NV is taking a similar approach. It is working on a test that can tell within 50 minutes which of 20 potential viruses and bacteria is causing a respiratory infection.

Still, there are stringent barriers to getting diagnostics into the hands of doctors in the U.S., where companies must satisfy regulators that their technology is simple enough for those without laboratory training. BioMérieux’s test currently is limited to specialist laboratories in the U.S., though it is already used by doctors in small clinics elsewhere, according to Mark Miller, chief medical officer at bioMérieux.

Other companies, such as Los Gatos, Calif.-based GeneWeave Biosciences Inc., have focused purely on identifying antibiotic resistance. Its “Smarticles” technology interacts with living bacteria to produce light. If the bacteria in question are drug-resistant, they will continue to shine in the presence of an antibiotic, signaling that the doctor should try a different drug. The test takes less than four hours and has already caught the eye of
Roche Holding AG’s
diagnostics arm, which in August agreed to acquire GeneWeave for up to $425 million.

Sunnyvale, Calif.-based
Cepheid
was one of the first companies to develop a hospital diagnostic for infections when, in 2007, it launched a one-hour test for methicillin-resistant Staphylococcus aureus, or MRSA. Its test, at around $40, is much more expensive than the slower lab test, which costs about a dollar. But Cepheid “was able to convince hospitals they’d save money in overall costs of care by stratifying patients” based on whether they had the resistant strain, according to Dan Leonard, analyst at Leerink Partners.

Still, innovative diagnostic technologies can struggle to gain momentum, according to Prof. Heneghan. The companies that make them normally don’t have the funds to run large-scale clinical trials to convince governments and other payers of their cost-effectiveness. According to analysis by health consultancy Diaceutics, it costs about $50 million to market and sell a novel diagnostic, almost as much as the $55 million needed to develop it in the first place.

A case in point is a rapid diagnostic test from Waltham, Mass.-based
Alere Inc.,
that helps doctors figure out whether a chest infection is serious enough to warrant the use of antibiotics. Ten years after it was launched, it is used in fewer than half of European countries, even though studies have shown antibiotic prescribing is around 20% lower in regions where it is used.

And despite the recent flurry of advances, Dr. Anthony Fauci, director of the U.S. National Institute of Allergy and Infectious Diseases, said the field isn’t moving fast enough. “We do not have an entire array of readily available, reasonably inexpensive” and accurate diagnostics that doctors can use, he said.

To spur more innovation in this area, groups in the U.K. and U.S. have launched publicly funded prizes and grants worth a combined $36 million for developing rapid diagnostics with the aim of curbing antimicrobial resistance. And the role of diagnostics is receiving more recognition as the threat of drug-resistant superbugs climbs the political agenda.

“Most casual, and some very informed, observers automatically think the main part of the problem is getting new drugs,” said economist Jim O’Neill, who is running a review on antimicrobial resistance for the U.K. government. “At least as big, if not bigger, is reducing the demand side, of which state-of-the-art diagnostics is front and center.”